In a world of misinformation, Fitness Pudding is here to separate fact from fallacy, and science from fiction.

Women, Weight Lifting and Big Muscles

Women, Weight Lifting and Big Muscles

The #1 reported barrier to weight training by women, is the fear of getting big muscles. This fear is very unfortunate, because (1) it is a fallacy, and (2) it prevents women from enjoying all of the wonderful benefits of weight training.

So, Why the Fear?

There are convincing arguments from both social and innate sides as to why these fears exist, and why they are so common.

Nature. Speaking generally, evidence suggests that most women are hard-wired, so to speak, to not to want to be big and muscular. Most women find it disgusting or unattractive for women to be too muscular (like a man), which may be associated with the natural desires to be distinct from man (i.e. sexually dimorphic). 

Nurture. Add to this natural fear, women are bombarded with social influences to be skinny, small or thin. Then, they stumble across pictures of women with big muscles, such as these photos of famous bodybuilders taken by photographer Martin Schoeller.


Clearly, there are muscular women out there who partake in some weight training. So, what gives?


The easiest way to debunk this fallacy, is to better understand testosterone. Testosterone is a male sex hormone produced in the testes, and stimulates muscle growth. Although a male sex hormone, women do naturally produce a little testosterone from the ovaries, for instance, but in very small amounts. To illustrate this difference, men have ~90% more testosterone than women. Men are teeming with testosterone. Women are not.

This is why I some women fear the simple aroma of testosterone from the "man-land" section of the gym will make them get bigger muscles!

Take Home Message 1: Women do not have enough testosterone to pack on large amounts of muscle.

Actually, men do not even have enough testosterone to build large amounts of muscle. Why do you think so many men take testosterone and other steroids? The amount of testosterone that is naturally produced is not enough to get to these large, muscular physiques. So, to look like large men, they must start giving themselves the horomones of a large man. It will not naturally occur from weight training.

Weight Training

Take Home Message 2. Testosterone does not respond well to weight training.

As you can see in the figure on the right1, 40- and 70-year old men (M40 and M70) were compared to 40- and 70-year old women (W40 and W70). hakinnen200 testosteroneBefore starting weight training (control period), we clearly see the large difference in tesosterone between men (~17 nmol/L of blood) and women (~1.5 nmol/L of blood).

Next, look at how the lines, for both men and women, change over 5 months of heavy strength training. They don't change!

In other words, even 5 months of heavy strength training was not enough to increase testosterone levels in men or women. So, how in the world could weight training cause women to get huge muscles?

It can't.

Take Home Message 3. Muscle growth requires specific weight training knowledge.

We all have some increase in muscle size when we do weight training consistently, and we want it. This growth is called "hypertrophy", and we should not fear it. The extra muscle enhances our metabolism, and improves strength, fitness and health.

However, to maximize any ability we do have to put on large amounts of muscle, requires a very specific knowledge of weight training. You are not going to accidentally train this way.db biceps curl

One quick example
A biceps workout for most of us may include 1 exercise, such as dumbbell biceps curls, done for 3 sets of around 10 repetitions each set.

If we are really feeling motivated, we may choose 2 biceps exercises, and do each exercise for 3 sets (6 sets total).

A bodybuilder will choose upward of 5 biceps exercises, and do 5 sets of each exercise, for a whopping total of 25 sets!

Take Home Message 4. Research results are misinterpreted.

In short, "statistical significance" tells us how confident we are that there is a difference, but does not tell us how big this difference is. Take for instance the following graph2. Chilibeck1997 muscle-growth

Notice the "**" above the 3rd bar, which tells us that there was a statistically significant increase in lean/muscle mass (kg) in the legs from pre to post, after 20-weeks of weight training in a sample of women.

The "**" just tells us that we are confident there is a difference in the amount muscle from pre to post, but does not tell us how big the difference is.

!! Notice that the actual difference is only 1 pound in both legs, and that was after 20 weeks of weight training!
Clearly, not enough of a difference to claim that weight training causes women to get big muscles.


Benefits of Weight Training

Now that this fallacy has been BUSTED!, I wanted to leave you with a few of the many wonderful benefits of weight training.
Go get 'em!

  • Improved body composition (even better than aerobic exercise).
  • Increased metabolism of up to 15% increase in resting metabolic rate.
  • Improved mental health, such as despression (as good as anti-depressant medications), self-confidence, self-esteem, and cognitive functioning.
  • Improved Body Image.
  • Strengthening of Muscles and Bones.
  • Improved Balance and Reduction of Falls.
  • Improved Glucose and Cholesterol Control.
  • Sleep Improvements

For more info... CDC | Mayo Clinic | Runner's World | National Institute on Aging



1Hakinnen, K., Pakarinen, A., Kraemer, W.J., Newton, R.U., & Alen, M. (2000). Basal concentrations and acute responses of serum hormones and strength development during heavy resistance training in middle-aged and elderly men and women. The Journals of Gerontology, 55(2), B95-105.

2Chilibeck, P.D., Calder, A.W., Sale, D.G., & Webber, C.E. (1997). A comparison of strength and muscle mass increases during resistance training in young women. European Journal of Applied Physiology and Occupational Physiology, 77(1-2), 170-175.



Are Setting Goals Good or Bad?
Jogging as Deadly as Sitting on Couch?